Synchros S300

The three JBL Synchros on-ear and over-ear headphones S300, S500 and S700 all have cables with remote control on them. There are two types of remote controls. One is for iPhones mainly. It has white dividing rings between the poles of the jack plugs. The other one is for Android phones. It has black dividing rings between the poles of the jack plugs. This is shown in the owner's manuals as a drawing. The S300 comes in two models, S300i and S300a. They are of course meant for iPhones and Android, respectively. You should either buy the i or the a version, to match the phone you have. But since the difference is only in the remote control on the cable, it is always possible to buy the alternative cable later, as long as they are in stock as spare parts. The S500 and S700 have BOTH cables in the box, so there is no i and a version of these models.